BitterMatch: Recommendation systems for matching molecules with bitter taste receptors

Bitterness is an aversive cue elicited by thousands of chemically diverse compounds. Bitter taste may prevent consumption of foods and jeopardize drug compliance. The G protein-coupled receptors for bitter taste, TAS2Rs, have species-dependent number of subtypes and varying expression levels in extraoral tissues. Molecular recognition by TAS2R subtypes is physiologically important, and presents a challenging case study for ligand-receptor matchmaking. Inspired by hybrid recommendation systems, we developed a new set of similarity features, and created the BitterMatch algorithm that predicts associations of ligands to receptors with ~80% precision at ~50% recall. Associations for several compounds were tested in-vitro, resulting in 80% precision and 42% recall. The encouraging performance was achieved by including receptor properties and integrating experimentally determined ligand-receptor associations with chemical ligand-to-ligand similarities. BitterMatch can predict off-targets for bitter drugs, identify novel ligands and guide flavor design. Inclusion of neighbor-informed similarities improves as experimental data mounts, and provides a generalizable framework for molecule-biotarget matching.

Altered Taste Function in Young Individuals With Type 1 Diabetes

Past studies on altered taste function in individuals with type 1 diabetes have yielded inconsistent results. We therefore evaluated taste recognition and possible association with personal and diseases characteristics in young individuals with type 1 diabetes and healthy controls. Taste recognition and intensity for 6-n-propylthiouracil (PROP), quinine, citric acid, sucrose, and sodium chloride were assessed using a filter paper method in 276 participants with type 1 diabetes and 147 healthy controls. Personal and clinical data were recorded for all participants during a baseline visit. Regression analysis was adjusted for sex, age, and standardized BMI. Overall, 47% of participants with type 1 diabetes vs. 63.5% of healthy controls recognized all tastes (p = 0.006). Moreover, a lower capacity for recognizing the bitter taste of PROP and the sour taste of citric acid was found in participants with type 1 diabetes compared to healthy controls (p = 0.014 and p = 0.003, respectively). While no significant effect of glycemic control on taste recognition was found, an association with lower age at onset emerged. Our findings suggest an impaired taste perception in individuals with type 1 diabetes, possibly linked to age at onset.

Sensory Drivers of Consumer Acceptance, Purchase Intent and Emotions toward Brewed Black Coffee

The link between coffee aroma/flavor and elicited emotions remains underexplored. This research identified key sensory characteristics of brewed black coffee that affected acceptance, purchase intent and emotions for Thai consumers. Eight Arabica coffee samples were evaluated by eight trained descriptive panelists for intensities of 26 sensory attributes and by 100 brewed black coffee users for acceptance, purchase intent and emotions. Results showed that the samples exhibited a wide range of sensory characteristics, and large differences were mainly described by the attributes coffee identity (coffee ID), roasted, bitter taste, balance/blended and fullness. Differences also existed among the samples for overall liking, purchase intent and most emotion terms. Partial least square regression analysis revealed that liking, purchase intent and positive emotions, such as active, alert, awake, energetic, enthusiastic, feel good, happy, jump start, impressed, pleased, refreshed and vigorous were driven by coffee ID, roasted, ashy, pipe tobacco, bitter taste, rubber, overall sweet, balanced/blended, fullness and longevity. Contrarily, sour aromatic, sour taste, fruity, woody, musty/earthy, musty/dusty and molasses decreased liking, purchase intent and positive emotions, and stimulated negative emotions, such as disappointed, grouchy and unfulfilled. This information could be useful for creating or modifying the sensory profile of brewed black coffee to increase consumer acceptance.

Influence of milk-clotting enzymes of animal and microbial origin on the quality and shelf life of soft cheeses

A comparative test was carried out for milk-clotting enzymes (MCE) of animal origin (Naturen® Extra), microbial origin (Marzyme®) and MCE based on recombinant camel chymosin (Chy-max® M) in the production of soft cheese “Lyubitelskiy”. By the end of the shelf life of the cheeses (12 days at a temperature of 3 ± 1 °C), differences were noted in the degree of proteolysis (DP) and the value of the complex modulus G*, which were the following ones for cheeses produced with MCE of the brands: Naturen® — DP = 17.86 ± 0.24%; G* = 4164 ± 587 Pa; Marzyme® — DP = 17.98 ± 0.49%; G* = 4581±786 Pa; Chy-max® M — DP = 9.85 ± 0.63%; G* = 7949 ± 1157 Pa. Cheeses made with Chy-max® M MCE had a denser texture than cheeses made with MCE of Naturen or Marzyme, which did not differ significantly in consistency. In the studied cheeses, the severity of the bitter taste was proportional to the content of water-soluble peptides with a mass of 0.5–3 kDa. Cheeses with Marzyme® MCE had a more intense bitterness than cheeses with Naturen® MCE. There was no bitter taste in cheeses produced with MCE of Chy-max® M. It was concluded that in the production of soft cheeses, recombinant camel chymosin can be used to increase the shelf life, and MCE of microbial origin can be recommended to replace more expensive MCE of animal origin.

3-oxo-C12:2-HSL, Quorum Sensing Molecule from Human Intestinal Microbiota, Inhibits Pro-inflammatory Pathways in Immune Cells via Bitter Taste Receptors

In the gut ecosystem, microorganisms regulate group behaviour and interplay with the host via a molecular system called quorum sensing (QS). The QS molecule 3-oxo-C12:2-HSL, first identified in human gut microbiota, exerts anti-inflammatory effects and could play a role in inflammatory bowel diseases where dysbiosis has been described. Our aim was to identify which signalling pathways are involved in this effect. We observed that 3-oxo-C12:2-HSL decreases expression of pro-inflammatory cytokines such as, Interleukine-1β (-3 %) and Tumor Necrosis Factor-α (TNFα) (40 %) by stimulated immune RAW264.7 cells and decreased TNF secretion by stimulated PBMC in a dose-dependent manner, between 25 µM to 100 µM. Transcriptomic analysis of RAW264.7 cells exposed to 3-oxo-C12:2-HSL, in a pro-inflammatory context, highlighted JAK-STAT, NF-κB and TFN signalling pathways and we confirmed that 3-oxo-C12:2-HSL inhibited JAK1 and STAT1 phosphorylation. We also showed through a screening assay that 3-oxo-C12:2-HSL interacted with several human bitter taste receptors. Its anti-inflammatory effect involved TAS2R38 as shown by pharmacologic inhibition and led to an increase in intracellular calcium levels. We thus unravelled the involvement of several cellular pathways in the anti-inflammatory effects exerted by the QS molecule 3-oxo-C12:2-HSL.

Sensory Profiles of Chocolate Drinks Made from Commercial Fermented Cocoa Powder and Unfermented Cocoa Beans

Polyphenols are the major bioactive compounds of cocoa beans. The addition of unfermented cocoa beans powder is used to enhance the functional properties of the chocolate drink. This study aimed to analyze the sensory profile of chocolate drinks made from a mixture of commercial cocoa powder and non-fermented cocoa beans by the projective mapping method. Seventy-five naive panelists tested four types of chocolate drink formulations and one benchmark (BM). The beverage formulations based on commercial cocoa powder consist of Formulations 1 (F1), F2, F3, F4 namely with the addition of 0, 10%, 20%, and 30% unfermented cocoa powder, respectively. The result showed that samples F1, F2, F3, and F4 had the dominant attributes of chocolate aroma, bitter taste, and bitter aftertaste. Whereas, BM has a dominant sensory profile of chocolate aroma, sweet taste, and sweet aftertaste. The highest value elevation (95o) is the benchmark (commercial chocolate powder drink). The next height value is in sample F1 which is located at an altitude of 20o-30o. Samples F2, F3, and F4 are the samples that have the lowest elevation (20o). Thus, the addition of cocoa powder from unfermented cocoa beans has not been accepted by consumers due to its bitter taste and bitter aftertaste.

Arjuna Coffee Organoleptic Test

The organoleptic test of coffee grown in the Toyomarto area aims to determine consumer preferences for coffee grown on the slopes of Mount Arjuna. The two types of coffee that are most in demand in the global market are Arabica and Robusta. When viewed from the level of consumption, around 70% of the world's population are consumers of Arabica coffee, which has a mild and aromatic taste. Meanwhile, the remaining 30% of the world's population are consumers of Robusta coffee, which has a bitter taste and 50% higher caffeine content than Arabica coffee. There is another type that is grown in Toyomarto, namely the Liberica type. Toyomarto Village, which is located in Singosari District, Malang Regency, is located at an altitude of 700-1200 masl. has a fertile soil that makes a specific and unique taste in the coffee that grows around it. Organoleptic testing has been carried out at 2 different locations. The panelists really liked the sour taste of Arabica coffee and the bitter taste of Robusta coffee. Meanwhile, Liberica coffee was less liked by the panelists.

Consumer Acceptability and Sensory Profile of Three New Celery (Apium graveolens) Hybrids and Their Parental Genotypes

Celery is a stalky green vegetable that is grown and consumed globally and used in many cuisines for its distinctive taste and flavour. Previous investigations identified the aroma composition of celery and profiled its sensory characteristics using a trained panel; however, evaluation of the sensory characteristics of celery combined with a consumer panel, where consumer preferences and acceptability are determined, is novel. In this study, three parental genotypes (12, 22 and 25) and three new hybrids (12x22, 22x12 and 25x12) were presented to a trained sensory panel (n = 12) for profiling and a consumer panel (n = 118), where liking and preference were assessed. Celery samples were analysed by SPME GC–MS and significant differences in aroma composition between all samples were identified, causing significant differences in the sensory profile. Furthermore, significant differences in attributes assessed for liking (appearance, aroma, texture and overall) were identified. Consumer segmentation identified three groups of consumers exhibiting differences in the hedonic reaction to the samples. Sweet and bitter taste along with overall flavour were identified as drivers of liking. Hybrid 25x12 was found to be the hybrid that exhibited high intensities for most of the attributes assessed.

Bacteria-derived peptidoglycan triggers an NF-kB dependent response in Drosophila gustatory neurons

Probing the external world is essential for eukaryotes to distinguish beneficial from pathogenic microorganisms. If it is clear that this task falls to the immune cells, recent work shows that neurons can also detect microbes, although the molecules and mechanisms involved are less characterized. In Drosophila, detection of bacteria-derived peptidoglycan by pattern recognition receptor (PRR) of the PGRP family expressed in immune cells, triggers NF-kB/IMD dependent signaling. We show here that one PGRP protein, called PGRP-LB, is expressed in some proboscis's bitter taste neurons. In vivo calcium imaging reveals that the PGRP/IMD pathway is cell-autonomously required in these neurons to transduce the PGN signal. We finally show that NF-kB/IMD pathway activation in bitter neurons influences fly behavior. This demonstrates that flies use the same bacterial elicitor and signaling module to sense bacterial presence via the peripheral nervous system and trigger an anti-bacterial response in immune-competent cells.